Polonium, elemental reactions with

Rutherfordium (Z = 104) cannot be produced directly in " Ca-induced reactions, as it would require a polonium target. The isotopes Rf (Jin. — 160 s) and Rf Ty2 — 1.3 h) are the terminating SF activities of the decay chains derived from and Fl, produced in " Pu(" Ca,xn) reactions with x = 5 and X = 3, respectively [8, 316, 353]. Rf activities produced in hot-fusion reactions with lighter heavy ions with much higher cross sections are generally more appropriate for radiochemical experiments (see Liquid-Phase Chemistry of Superheavy Elements and Gas-Phase Chemistry of Superheavy Elements ). However, the long half-life of Rf may provide the means for previously unexplored radiochemical investigations. 

Evidence for the existence of PoS is much stronger. Aqueous solutions in HCl containing Po and Po yield a precipitate of PoS. During the course of this reaction, Po is reduced to Po with the concurrent oxidation of sulfide to free sulfur. The same sulfide can be prepared by the reaction between polonium hydroxide and ammonium sulfide. The compound has not been successfully prepared by the direct reaction between the elements. 

However, in regard to the reactions of tungsten with metallic elements, the situation is quite different. A large number of metals exist which fail to react with tungsten, like the alkali metals, the alkaline earth metals with the exception of beryllium, the rare earth metals with the exception of cerium, and especially the elements scandium, yttrium, lanfiianiun, copper, silver, gold, zinc, cadmium, mercury, indium, thallium, tin, lead, antimony, bismuth, and polonium. 

The reactions of polonium vapour with both Main-group and Transition-group IV elements have been studied. Polonium vapour did not react with Si, Ta, or Zr carbides, but did react with tin at 370 °C to give a tin polonide, which dissociated at 670 °C to the elements. 

Marie Curie went on to win a second Nobel Prize, this time in chemistry in 1911, for her discovery of radium and polonium. She was the first scientist noted for making the claim that radioactivity derives from within the atom and not by virtue of some unknown chemical reaction. This was the genius of Madame Curie, a woman immortalized through element 96 curium, with deep insightto the nature of the atom long before it s properties were revealed to the world. 

There are at the moment 115 known elements with atomic numbers 1-115. Of these, 93-115 exist only as the results of nudear reactions. Strictly speaking the natural elements are less numerous than 92 as some occur only as radioactive isotopes with such short half-hves that their concentrations in nature are extremely low. These special elements are 43 technetium, 61 promethium, 84 polonium, 85 astatine, 86 radon, 87francium, 88 radium and 89 actinium. 

Becquerel s work was continued by a young Polish graduate student in Paris named Marie Sklodowska Curie (1857-1934). Curie chose the study of uranic rays as the topic for her doctoral dissertation. Rather than focus on the rays themselves, as Becquerel had, she began to search for other substances that might emit uranic rays. She was a brilliant chemist and, with the help of her husband, Pierre Curie (1859-1906), she found two other substances that emitted these rays, one of which was a previously undiscovered element. She writes, We therefore think that the substance that we have extracted. . . contains a metal previously unknown. We propose to call it polonium, after the native land of one of us. Since the Curies discovered that uranic rays were not unique to uranium, they changed the name from uranic rays to ray activity or radioactivity. By further experimentation, they deduced that radioactivity was not a product of a chemical reaction, but instead, a product resulting from changes within the atom itself. 

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